Spot the (alleged) criminal Musician Politician Estate agent What are their alleged crimes?
Physiological theories • Theories that link criminal behaviour to biological form and function • Atavistic form (Lombroso) • Somatotype (Sheldon) • Extra Y syndrome
Atavistic form theory • Lombroso (1876) • Criminality is inherited • Genetic transmission of throwback/atavistic (i.e. primitive) features • Physical features indicate criminal tendencies
Can you tell whether someone is a criminal just by looking at them? • How would you test this idea scientifically?
Lombroso (1876) • A number of significant flaws: • Lack of a control group for comparison • Sample included people with psychological/physiological disorders • ‘Crime’ is a social construction • ‘Single defective gene’ theories - doubtful
Lombroso (1876) • A number of significant contributions: • Later believed that most criminality was ‘acquired’ – environment, poverty, education • Shifted study of crime to an empirical basis • ‘The father of modern criminology’ (Shafer, 1976)
Somatotype theory • Sheldon (1949) • ‘Constitutional psychology’ • Criminality is linked to temperament • Temperament is linked to bodily build • Ectomorph • Endomorph • Mesomorph
Sheldon (1949) Source: www.pponline.co.uk Relaxed and hedonistic Energetic and adventurous Solitary and restrained
Sheldon (1949) • The mesomorph’s personality makes him more likely to engage in criminal activity • Thousands of photographs rated 1 – 7 for mesomorphy • College students & delinquents compared • Delinquents had higher mesomorphy ratings (4.6 vs. 3.8)
Sheldon (1949) • Sheldon’s constitutional psychology is no longer taken seriously • But there is a small association between bodily build and criminality. How could this be explained? • Influence of testosterone on body and behaviour? • Effects of stereotyping and labelling?
Last year you looked at the effects of sex chromosome abnormalities on development. What did you learn?
Chromosomal abnormalities XY XXY XYY Male with feminine characteristics Male with exaggerated male characteristics
Chromosomal abnormalities • ‘Extra Y’ syndrome was suggested to lead to: • High testosterone levels • Powerful bodily build • Heightened aggression • Propensity for violent crime
Chromosomal abnormalities • XYY males not actually as predicted (Graham et al, 2007): • Normal testosterone levels • Normal aggression levels • Taller, but not necessarily more powerful • Prone to developmental disorders and learning difficulties
Chromosomal abnormalities • XYY males are rare in the general population and over-represented in the offender population • However, their crimes are not violent ones • So why are XYY men at a greater risk of offending?
Single factor theories of criminality are always likely to fail • ‘Crime’ is not a natural or homogenous category of behaviour • It is self-evidently the result of interaction between a range of factors • Different explanations for different types of crime